const fs = require('fs');
let promise = new Promise((resolve,reject)=>{
  fs.readFile('./1.txt','utf8',(err,result)=>{
    if(err!=null) {
      reject(err)
    } else {
      resolve(result);
    }
  })
})

promise.then((result)=>{
  console.log(result)
}).catch(err=>{
  console.log(err)
})